BIRDS OP PREY. OWLS. 3:21 
and research are alone necessary to give the same sta- 
bility to the minor divisions. In the mean time we 
shall mdeavotcr to make some approximation to this 
object by exercising our own judgment as to the rank 
of the subordinate types, that is, all such as exhibit 
those representations above alluded to ; without pre- 
suming, however, to attach to our opinion that weight 
which further knowledge and analysis can alone impart. 
(257.) The STRioiDiE, or Owls, exhibit the full 
development of that singular ruff of close.set feathers 
round the head, the first indications of which are seen 
in the henharriers (Circus C.). Their nocturnal habits, 
their large eyes, singularly shaped ears, and soft downy 
plumage, arc well known. This structure is admirably 
adapted to their peculiar economy. Great powers of 
sight and hearing are absolutely essential to these birds, 
whose habits are nocturnal, more particularly as they 
hunt after many small quadrupeds which only venture 
from their retreats after sunset. No sound in the air 
should tell the approach of the owls : their flight, by the 
peculiar construction of the wing feathers, is, therefore, 
rendered noiseless, and they come upon their prey 
silently and surely. The wings of the goatsuckers 
(Caprimulyida) alone, of all other birds, exhibit a 
similar conformation. In both these, the tips of the 
external bars of the outermost quill feathers, instead of 
lying flat upon each other, in the ordinary way, are 
detached and curved outwards, so as to resemble the 
teeth of a fine saw ; hence it follows that when the air 
is beaten by wings so formed, there is no reverberation. 
The opposite extreme of this structure is seen in the 
gallinaceous birds, where the external barbs are very 
stiff, and pressed close upon each other : this formation 
of w'ing causes the air to he suddenly and abruptly ex- 
pelled from beneath it, and occasions that loud whirling 
noise, often startling to the unprepared pedestrian, 
with which the partridge ascends from the ground and 
seeks refuge in flight. The whole structure, in fact, of 
the wings of the owl is evidently intended to promote a 
Y 
